Military

Further Reading

A-X Attack Fighter - Design

Pierre Sprey wrote the requirements for the A-X fly-off. The development concept paper for the A-X stated that the Air Force envisions three major types of operations for this aircraft. One type of operation was called airborne loiter alert, in which the A-X will orbit over the battlefield; this operation will be used where minimum aircraft response time was critical. The second type of operation was called forward-operating locations, which would be within, say, 25 miles of the forward edge of the battle area and which would be used in operations involving rapid ground force movements. The third type of operation was called mainbase operations, which were air bases within 150 miles of the forward edge of the battle area and which would be ,used for preplanned (for example, the day before) strikes, armed escort, and reconnaissance missions.

One of the prime, if not the. most important, requirment of a Close Air Support aircraft is the ability to effectively deliver ordnance on the target mithin minutes after the reqnest is submitted. Kesponsivenes can be achieved by either loitering in the battle area or by operating from formard baees. The A-X would have the required design capability to operate from austere bases, short take-off and landing, and ease of maintenance.

In a possible "mid-intensity" conflict with the Warsaw Pact countries, the most serious threat to close-air-support aircraft was expected to be the Soviet Union's radar-controlled Quad 23 mm and Twin 57 mm antiaircraft artillery. The A-X's critical components were to be invulnerable to projectiles 'up to 14.5 mm, but it was not clear how survivable the A-X would be when it encountered the larger weapons. The Office of the Secretary of Defense-Joint Staff Service Group report dated June 22, 1971, presents three widely different sets of figures about the size of the vulnerability areas of the two A-X designs without indicating which set of figures it believes to be the most realistic,

Interestingly enough, in the original speci{ication to the contractors, the type o{ engine (reciprocating, turboprop or
turbofan) and the number were left to the contractors to decide. One contractor submitted a proposal for turboprop, mhile the remainder recommended the turbo{an engine. It was found that the turbofan engines mould give the same capability as the turboprop on the low end of the airspeed spectrum and additional capability at the high end of the spectrum. The V/STOL concept was eliminated because it would cost 30-100 percent more, longer development time was required, adequate payload and loiter capabilitu mere lacking.

Unlike most of the Air Force's aircraft assigned to close air support, the A-X would have a STOL capability to operate from forward airstrips of about 1,OOO-foot lengths. The development concept paper called for the A-X to carry 6,500 pounds of payload (weapons and fuel) when operating from such airstrips. It called for the A-X also to be capable of loitering in the air for 2 hours while carrying eighteen 500-pound bombs on a 250 nautical wile radius mission, The aircraft, having an intended maximum gross weight of about 38,000 pounds, would be capable of carrying 16,000 pounds of ordnance and ordnance pods. A cruise speed of 345 miles an hour and a maximum level flight speed of 460 miles an hour were being sought.

The A-X was to be a single-place, subsonic aircraft having twin turbofan engines. Although the physical and performance characteristics would vary with each contractorrs version, it would be about 54 feet long and about 16 feet high; it would have about a 55-foot wingspan and would weigh about 19,000 pounds. Armor plating would be provided for protection against 14.5 mm and smaller projectiles. For protection against total fuel drainage upon being hit, separate fuel tanks and redundant lines would be included. Other safety features would be included in its design to minimize fire and explosives hazards.

According to the concept formulation package, the A-X would be capable of carrying the full range of weapons suitable
for close aLr support, such as Rockeye antitank munitions, 500-pound general-purpose and laser-guided bombs, Napalm, and so forth. The development concept paper also stated that the aircraft would carry the MAVERICK antitank missile and that SIBEWINDER air-to-air missiles would give it a degree of protection against enemy fighters. These various weapons would be carried on the 10 wing stations of the aircraft.

A high degeee of accueacu would be obtainable through the ability to estabish the A-X on a 4S° dive at 275 knots. This would allow the pilot to track the target easier and get closer to the target before initiating pullout. Ohe low end of its airspeed spectrum would enhance the pilot's ability to acquire targets, stay close to the target and re-attack if needed.

A 3Omm, high-muzzle-velocity, automatic cannon was being developed to give the A-X a specialized "tank ki%lingss weapon. It was to be a forward, fixed-firing gun to be located on the underbelly of the aircraft. Ammunition for the gun would be stored internally, and different types of rounds are to be selectable by the pilot. Although the gun was not scheduled to be ready when the A-X competitive prototype flyoff was conducted in l972, the Air Force anticipated that the aircraft and gun would interface properly.

The A-X was to have a simple avionics subsystem. It would include the necessary communications equipment for eoordination with the supported ground forces, tactical air control, friend-or-foe identification, and so forth, Navigation aids would consist of a tactical air navigation systaS a heading and altitude reference system, and an automatic direction finder. Some target acquisition would be accomplished with a laser seeker, and weapons delivery would be accomplished visually. The Air Force had no programmed equipment for night and adverse weather operations, although the Air Force said that more sophisticated avionics may be added later at additional cost.